The present disclosure relates generally to heat exchangers. Specifically the disclosure relates to a method of repairing a fluid circuit in a heat exchanger.
Fluid circuits in heat exchangers may experience extreme variances in thermal cycles leading to thermal stresses on components. For example, when installed in an aircraft air conditioning system, to cool air from the engine compressor for circulation in the aircraft cabin, with air drawn in from the atmosphere, the temperature of the atmospheric air, and the temperature of the engine compressor air may vary widely. These varying temperatures may cause expansions and contractions of elements of the heat exchanger, and the rates of these expansions and contractions may vary between components of the heat exchanger. The resultant thermal stresses may cause cracks, apertures, or other damage or wear to the heat exchanger and in particular to channels or tubes in the heat exchanger. The atmospheric air drawn into the engine and the heat exchanger may contain particulates and corrosive materials such as sulfuric and nitric acids. Exposure to and/or contact with these substances may also cause cracks, apertures, or other damage or wear to the heat exchanger.
As a result of damage and wear, fluid circuits in the heat exchanger may leak fluid above an acceptable level. To remedy this, the heat exchanger or components of the heat exchanger, such as a fluid circuit, may be removed from the aircraft or other application, repaired, and reinstalled. Some traditional repair methods of heat exchanger fluid circuits, including fluid channels such as tubes, include sealing the leaking channels or tubes by plugging them with mechanical seals or through a welding process. If too many channels or tubes are plugged in this manner, the heat exchanger may not function acceptably and may need to be replaced. Additionally, repairing a heat exchanger by plugging leaking channels or tubes may require disassembling the heat exchanger which may require a longer time period than desired.
As can be seen, there may be a need for a heat exchanger repair method which minimizes the repair period and increases the useful life of the heat exchanger.